Identify the false statement regarding type IX secretion systems (T9SS).
a. Proteins secreted by a T9SS have a C-terminal signal sequence.
b. Proteins secreted by a T9SS fold in the cytoplasm.
c. Proteins secreted by a T9SS are translocated by the Sec system.
d. Proteins secreted by a T9SS are attached to the LPS in the outer membrane.